Switching appliance for telephone-exchanges.



PATENTED SEPT. 12, 1905.

G. M. HEDMAN.

SWITCHING APPLIANCE FOR TELEPHONE EXCHANGES.

APPLIOATION IILEI) MAY 22, 1902.

UNITED STATES Para N1 OFFICE.

CARL M. HEDMAN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS.TO STROMBERG-CARLSON TELEPHONE COMPANY, OF ROCHESTER, NEW

MANUFACTURING YORK, A CORPORATION OF NEW YORK.

' SWITCHING APPLIANCE FOR TELEPHONE-EXCHANGES.

No. 799,160. Specification of Letters Patent.

Patented Sept. 12, 1905.

Application filed May 22, 1902. S i l No. 108,531.

To It whom, it nuty concern.-

Be it known that I, CARL M. HnnuAN, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Switching Appliancesfor Telephone-Exchanges, of which the following is a full, clear,concise, and exact description, reference being had to the accompanyingdrawings, forming a part of this specification.

My invention relates to switching appliances, and has for its object theprovision of an improved apparatus of this kind by means of which changeof circuit conditions may be readily effected.

My invention is particularly applicable in connection withtelephone-exchanges and provides a construction in which a plurality ofchanges of circuit conditions may be eli'ected, the switching appliancebeing of such a character as to be self-lockingin one position, theconstruction being designed to enable the operator of atelephone-exchange to readily effect the change in circuit conditionsnecessary in interconnecting subscribers for conversation.

More particularly my invention is designed to provide a new ringing andlistening key for telephone-exchanges in which the space occupiedthereby is reduced to a minimum and in which the wearupon the operatingparts is reduced to the lowest possible amount.

I will describe my invention more in detail by reference to theaccompanying drawings, illustrating the preferred embodiment thereof, inwhich----- Figure 1 is a side view of an improved key constructed inaccordance with my invention. Fig. 2 is an end view thereof. Fig. 3 is atop view thereof. Figs. 1 and 5 are side views illustrating the same inits various operating positions. Fig. 6 is a side View with the springsremoved.

Like characters of reference indicate like parts throughout thedifferent figures.

My improved key comprisesa suitable yoke 1, which has a hollow box-likebase 2 for supporting springs, and which has a bifurcated top comprisingthe sections 3 3, between which the actuating switch-plate 1 is adaptedto be supported.

The switch-plate -:L is pivotally mounted by means of a pin 5 and issupplied with a'handle 6 for causing a suitable actuation thereof. Theswitch-plate 1 carries two sets of rollers 7 and 8, pivotally mounted,respectively, by means of screws 9 and 10 upon the base portions of thesaid plate at opposite sides of the yoke 1, as shown most clearly inFigs. 1, 1, and 5.

The bottom portion of the switch-plate at is cut away to form with theends of said cut-. away portion detents l1 and 12, which are adapted toengage the central portion of the yoke 1 upon a suflicient actuation ofsaid switch-plate. The yoke 1 is adapted, by means of its upper sections3 3, to be secured to the table 13 of the telephone-switchboard. Iemploy four sets of springs, each set comprising a centralswitching-spring14, which is adapted in one position or another to beelectrically connected with springs 15 16, placed on either sidethereof. The rollers 7 and 8 are adapted to engage the springs 14 14:,one roller being provided for each spring 14. The rollers are normallyin engagement with said springs and are adapted to move either springout wardly, depending upon the direction in which the switch-handle 6 ispressed.

\Vhen the switch-handle 6 is in its central position, theswitching-springs 14: 11 are electrically connected, respectively, withthe springs 15 15, and when either spring 141s pressed outwardly thesame engages its alternate contact-spring 16. hen the key by virtue ofan actuation of the switch-handle 6 assumes the position as shown inFig. 4:, the rollers 7 are actuated a distance sufficient to place themon top of the straight surface of the left-hand springs 14, so that thesaid springs, jointly with the roller, retain the switch-plate 41,together with the switch-handle, in its actuated position, no tendencyto press the same back being exerted. The detent 12 upon theswitch-plate 4c prevents too great a movement of said switch-plate. Thisposition of the key is preferably utilized for listening purposes, as iswell understood. When the switch-handle 6 is moved to the oppositeposition, the detent 11 prevents a movement thereof sufficient to allowthe roller 8 to engage the straight surface of the spring 14, so thatthe spring always exerts sidewise pressure against the switch-plate, andthe key in that position is not locked. This" is the ringing position ofthe key, which is not desired to be self-locking, as is well understoodby those skilled in the art.

By means of the rollers which I employ the friction of the operatingparts is reduced to a minimum and the wear consequent upon the frequentactuation of the key is materially reduced.

The great advantage of mounting the springs, as shown, in verticalposition upon a yoke with the actuating-arm, as shown, will also bereadily apparent to those skilled in the art, as very little space. isoccupied by the key when in place upon the key-shelf in the switchboard.Pieces of insulation 17 17 are inserted between the springs 14, 15, and16, and screws 18 are employed to hold the whole structure in place uponthe yoke 1. An insulating distance-piece 19 is fixedly secured in theyoke l and retains the springs in correct position.

It will be apparent that many changes and modifications maybe made in myinvention without departing from its spirit, and I do not wish to limitmyself to the precise construction and arrangement as herein set forth;but,

Having thus described my invention, I claim as new and desire to secureby Letters Patent- In a switching apparatus, the combination with asupporting-frame 1, of a transverse member 3 at the top thereof and asupporting-base 2 at the lower end thereof, circuitchanging springsmounted at each side of said supporting-base and extending upwardlytoward the top transverse member, a switchplate 1 pivoted at 5 at theupper end of said supporting-frame, a handle 6 for said switchplate,cylindrical studs 8 and 9 at the lower end of said switch-plate, one ateither side thereof, actuating-springs 14: for the circuitchangingsprings associated with said studs, said actuating-springs 14 havingtheir upper ends bent transversely, and detents 11 and 12 on saidswitch-plate, the detent 12 being at a greater distance from the centerof the switchplate, said detent 12 upon actuation of the handle 6 towardthe right allowing sufficient movement of the switch-plate to carry thestud 9 to the top of the transverse end of the correspondingactuating-spring 14 where: by the switch-plate is locked in position,the detent 11 upon actuation .of the handle toward the left preventingsuflicient movement of the switch-plate to'carry-the stud 8 to the topof the transverse end of the corresponding actuated spring 14:.

In witness whereof I hereunto subscribe my name this th day of May, A.D. 1902.

CARL M. HEDMAN.

Witnesses:

HARVEY L. HANSON, J OHN' STAHR.

